Hi everyone. Just after a quick bit of advice. Basically, ive just painted my autosleeper trident white (not just any white, but geet bright dayglo eff off white

) so the main body is beautiful but my gel coat hightop roof is yellowed from its 30 years of age , and now ot sticks. Out like a sore thumb. What you guys recomend to take the oxidation off and take it back to clean 'just off white' as opposed to yellow?? Many thanks
Michael